Over the last few years, as ratings for cable networks like AMC and TLC have surged, their brand identities have shifted just as dramatically. History, the channel that five years ago was known for its dusty old World War II documentaries, is now better known for reality shows about swamp-dwellers and the miniseries “The Bible.”

The notable exception to the rule is USA , which has remained the No. 1-rated entertainment network in cable for the last 7 years despite (or perhaps because of) the remarkable consistency of its content. An average of 3 million viewers a night tune in to USA’s so-called “blue skies” programming, series like “Burn Notice,” “Royal Pains” and “Covert Affairs” that combine sunny locales and quirky characters with exotic or otherwise interesting jobs.

It’s a formula that’s worked beautifully for the network, but now, under the guidance of co-presidents Jeff Wachtel and Chris McCumber, USA is branching out aggressively.

“We really think that we’re taking the next step in a natural evolution,” said Wachtel.

It all began last month with “The Moment,” the channel’s first reality program -- sort of a “Made” for grown-ups. Two more unscripted series, “The Choir” and “Summer Camp,” are scheduled for later this year.

The expansion continues on June 6 with the premiere of “Graceland,” a gritty (by USA standards) serialized drama about a group of undercover federal agents living in a Southern California beach house.

But that’s not all: On Thursday, the day of its upfront presentation in New York City, USA announced series orders for its first two half-hour sitcoms, “Sirens,” from executive producer Denis Leary, and “Playing House,” created by and starring Jessica St. Clair and Lennon Parham. This is on top of landing the syndication rights to “Modern Family,” which will begin airing on the network Sept. 24.

And this summer, production is set to begin on “Horizon,” a WWII drama about an FBI secretary who undertakes a secret investigation. From Gale Anne Hurd, executive producer of “The Walking Dead,” it’s the first period piece on USA since the 2003 western series “The Peacemakers.”

That means the network will experiment with three new genres in less than a year, which begs the question: If it ain’t broke, why fix it?

“We’ve got a great loyal audience.We know for a fact that it’s higher than any other network out there,” said McCumber, citing internal research indicating that USA viewers are likely to watch multiple shows on the network. “Our opportunity now is bring in more viewers who’ll be just as loyal.”

He brings up the example of “Suits,” the legal drama that debuted in 2011. Though it was seen as a creative departure at the time, it’s attracted a new, younger, male demographic without disrupting the USA brand identity.

Wachtel and McCumber are hoping that “Modern Family” will also bring new eyeballs their way. “We found there is only about an 8% overlap between USA viewers and those who watch ‘Modern Family,'” McCumber said.

The deal for the syndication rights, brokered back in 2010, was the first step in a long-term strategy to develop original comedies. The idea is to ease the USA audience into comedy with “Modern Family,” then launch “Sirens” and “Playing House” early next year. The network is also reportedly considering reviving the recently canceled ABC sitcom “Happy Endings.”

From “White Collar” creator Jeff Eastin, “Graceland” shares some DNA with USA’s other one-hour dramas – namely, a picturesque setting and a conspicuously attractive cast – but it’s also darker (hint: heroin is involved). The network has also taken unusual steps to market the series to audiences who otherwise might not tune in to USA, promoting it at the SXSW Festival earlier this spring.

Still, there’s an inherent accessibility and optimism to the show that makes it a fit with the USA brand, according to Wachtel. “It’s still a very straightforward premise -- cops who move into a house on the beach -- and it has a wonderful theme to it, which is how do you go out and deal with some of the worst elements in the world and create a true family?”

In other words, don’t expect USA to “break bad” anytime soon.

“We’re not dissolving bodies in acid,” Wachtel said, “but Chris and I have great respect for our counterparts in the cable world.”